Crime Scene Training

Forensic Metal Fingerprinting

Simple, Handheld Device, Which Can Measure Corrosion On

Machine Parts

Science Daily,

June, 2013

Oct. 22, 2010 — Groundbreaking research into fingerprint detection developed at the University of Leicester now has an industrial application, thanks to a new invention by the scientist who developed the technique.

Dr John Bond's method of identifying fingerprints on brass bullet-casings, even after they have been wiped clean, was based on the minuscule amounts of corrosion which can be caused by sweat. First announced in 2008, this breakthrough was cited as one of the technologies 'most likely to change the world' by a panel of experts for BBC Focus magazine and was included in Time magazine's list of '50 best inventions of the year'.

Now, working with scientists in the University of Leicester Department of Chemistry, Dr Bond has applied the same technique to industry by developing a simple, handheld device which can measure corrosion on machine parts. Corrosion leads to wear and tear and needs to be carefully monitored so that worn parts are replaced at the appropriate time so this invention should prove a boon to the manufacturing sector.

"This is a new, quick, cheap and easy way of measuring the extent of corrosion on copper and copper based alloys, such as brass," explains Dr Bond, who is an Honorary Research Fellow in the University's Forensic Research Centre and Scientific Support Manager at Northamptonshire Police.

"It works by exploiting the discovery we made during the fingerprint research -- that the corrosion on brass forms something called a 'Schottky barrier' -- and we use this to see how much the metal has corroded.

"Such measurements can already be made but this is quick, cheap and easy and can be performed 'in the field' as it works off a nine-volt battery."

Dr Bond said: "Measuring corrosion of metal such as brass is important to ensure that machinery does not operate outside its safe limits.

"This could be anything from checking that a water pipe will not burst open to ensuring that the metal on an airplane is not corroded. This could lead, for instance, to the wheels falling off a jet. Having a corrosion measurement means for copper and alloys such as brass that is quick portable and cheap enables metals to be tested in situ with no prior set up of a corrosion measuring device.

"Also, rather than simply saying that the brass is corroding (as a technique such as weighing the brass would) this technique enables the type of corrosion to be determined (i.e. copper oxide or zinc oxide corrosion). As to which one it is gives clues as to how severe the corrosion is.

"This can be done already with something like X-ray photoelectron Spectroscopy (XPS) but that is lab based and very expensive to use. Our technique works off a 9-volt battery. In that sense, it won't tell you any more than XPS can, it is just quicker, cheaper and easier.

"A common use of brass in industry is heat exchangers as brass is a good conductor of heat. If these are water based, then seeing how the water is corroding the brass is useful. Also, you simply need to be able to touch the brass with a probe, there is no other setting up required. It's as easy as taking your temperature with a thermometer."

There is much research on inhibiting the corrosion of brass because of its use in heat exchangers and industrial pipe work, this technique enables the degree of corrosion to be easily measured.

A description of the prototype device has been published in the journal Review of Scientific Instruments. Dr Bond and his colleagues are now looking for a company which could exploit the invention and place it on the market.

BloodTips-06 Lumiscene Detects Invisible Blood Using a Different Approach

 Lumiscene Color Analyzer Result

Lumiscene is revolutionary water based, chemical blood detection method. Lumiscene helps to 
visualize latent/ invisible (e.g. washed or removed) blood stains and patterns through a chemiluminescence reaction and is specifically for use in crime scene forensic investigations. This chemical formula is based on luminol and fluorescein and has many superior qualities and advantages over classic luminol or tablet based luminol chemistry.

Advantage 1.

When a luminol solution comes in contact with blood the chemical luminescence emits dark blue light. When this emission spectrum is measured with a spectrum analyzer we see that the highest intensity is about 425 nanometers (nm).

 Instead of emission at 425 nm. Lumiscene has its emission peak at 525 nm, when it comes in contact with blood. Thus, the “light” produced by the chemical luminescence of Lumiscene is light blue/green in color.

This emission of 525 nm benefits the naked eye visibility of latent bloodstains multiple times.  Thus, in dark environments, the human eye is far more sensitive to the 525 nm. emission than to the emission of 425 nm.

 Advantage  2

The presence of fluorescein in the Lumiscene solution does not only change the emission spectra, it also acts as an enhancer of the chemiluminescence reaction and creates greater light intensity.

 Advantage 3

Most luminol solutions, whether tablet based or not, and fluorescein solutions contain hydrogen peroxide as an activator. Well known in the scientific community is the damaging effect of hydrogen peroxide on DNA. Since in forensic investigations the quality and/or  quantity of the blood is not known, it is not recommended to apply a chemical solution with a high concentration of hydrogen peroxide. So the volume percentages of hydrogen peroxide should be kept to a minimum to minimize DNA damage.    

The Lumiscene stock solution is activated by 2 calibrated hydrogen peroxide tablets, which will give the solution an extremely low hydrogen peroxide volume: less than 0.12% compared to the usual 3% and as shown in other substances and in over 800 tests, preformed much better than normal luminol solutions.

 Advantage 4

Lumiscene, like luminol, is sprayed in darkness and therefore it is difficult, if not impossible to see with the naked eye, to check if the complete investigated area coming into contact with the solution. When using Lumiscene the user can check the investigated area by using an alternate light source such as the BLUEMAXX-series of lights and orange goggles/filter. Where Lumiscene is sprayed, the dried droplets will fluoresce when examined by a forensic light source between 415 and 480 nm.  

                                                           Lumiscene solution viewed under 455nm light and  orange filter                 

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Lighting Methods for Copy and Evidence Close-up Photography

From the

Crime Scene and Evidence Photographer's Guide
Second Edition
Copyright ©2005

By Steve Staggs

The following lighting methods are effective for photographing various evidence subjects. The effects should be previewed in order to select the best lighting technique for the evidence subject.

Direct Lighting

Direct lighting uses normal copy lighting with one or more light sources at a 45-degree angles.

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Direct Reflective Lighting

Light is reflected directly off the subject into the lens. Place the subject at a 10-degree angle from the lens to film plane and place the light source at 10-degree angle from the subject. The light source reflects at a 20-degree angle into the lens. The light source may need to be diffused to prevent hot spots. This method creates very high contrast.

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Oblique Lighting

Oblique lighting uses a light source at a low angle, usually to show detail by creating shadows in the subject surface. It is commonly used when photographing impressions, tool marks and certain types of fingerprints.

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Bounce Lighting

Light is bounced off a white or reflective surface. The bounce surface may be positioned at different locations (above or to one side of the subject) to create the desired effect. This usually produces even non-glare lighting with low contrast.

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Diffused Lighting

An opaque material is placed between the light source and the the subject to diffuse the light. This usually results in even lighting with reduced reflections and hot spots.

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Transmitted Lighting

With transparent subjects the light source is transmitted through the subject toward the lens. The angle of the transmitted lighting is adjusted from 90 degrees to 45 degrees for the desired effect.

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Front Directional or Axis Lighting

A clear piece of glass is placed between the subject and lens at a 45-degree angle. The light source is positioned parallel to the film place and 45-degrees to the glass. While the light is transmitted through the glass, some is reflected downward directly on the subject. This technique is effective when photographing fingerprints on mirrors and into glasses or cups.

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Copyright Information

The images and excerpts from the Crime Scene and Evidence Photographer's Guide Second Edition  found on this World Wide Web page are copyright ©2005 by Steven Staggs. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means without written permission from the author, except you may download, reprint, reproduce and share the images and information on this World Wide Web page for non-commercial, private purposes. However, you may not manipulate or alter in any way the images and information. All artwork and photography is by the author.

Excavations of Skeletal Remains From an Anthropological Point of View

by Danny Rinehart 

Rinehart Forensics

Spring, Texas 77388  

Republished from Crime Scene Investigator Network

Introduction:

 Mankind has waged war for centuries. The twentieth century has become an age of genocide, atrocities and mass graves. The first recorded opening of mass graves in this century was during the Second World War. In the spring of 1940, the Soviet Red Army executed Polish army officers and prisoners of war. They were buried secretly in mass graves, some located in a forest near the village of Katyn in Belarus. Three years later this burial site was detected by the Germans and more than 4,000 bodies exhumed. Since the end of that war in 1945, only geographic boundaries have changed. In the past decades, civil wars in South and Central America, Asia, Africa and lately in Europe have taken the lives of hundreds of thousands of people.

 The worst genocide in the Baltic region took place during the war of 1991-1995 on the territory of former Yugoslavia, especially in Bosnia-Herzegovina (BiH). Under the guise of "ethnic cleansing," about a quarter of a million people lost their lives. Another two-and-a-half million became refugees. As of June 2000, according to the International Committee of the Red Cross, there are an estimated 15,000 to 20,000 missing persons. They may be buried in mass graves in the forests, fields or hills of their homeland. They may lie undetected on the surface waiting to be discovered, identified and returned to their families for proper burial.

 Beginning early in 1996, the first "after-the war-exhumations" in the territory of Bosnia-Herzegovina took place. No one was prepared for the task of exhuming the incomprehensible number of bodies or skeletal remains. In the first year of exhumations, almost 2,000 remains were recovered in BiH, and this is but a fraction of the missing or presumed dead. There are still thousands of bodies to be exhumed and examined in the coming years. The main purpose of opening the mass graves or the clearing of unburied surface remains is to identify the deceased and return them to grieving families. Unfortunately, the problems of identification are compounded by the lack of documents, distinctive clothing or personal belongings. Therefore, expectations for eventual identification of unknown remains lie in the ability of the forensic specialists to estimate age, gender and stature of skeletal remains based upon existing anthropological standards and DNA.

 Working with the International Commission for Missing Persons (ICMP), in Bosnia-Herzegovina, I was exposed to gravesites where different exhumation teams were making recoveries. These sites and many more are being investigated for humanitarian reasons in the hopes of identifying the remains with their respective families.

 Excavation of graves 

Prior to organizing an excavation of a suspected grave (mass or single) some basic background information about the number or victims, year of burial and type of grave (e.g.: dug hole, natural depression, cave) must be obtained. This information will assist in planning for resources, equipment, number of workers and the amount of time that will be necessary to perform recovery of remains. This is the most critical issue for a successful excavation, and it is imperative that reliability regarding this information is confirmed.

 Locating Suspected Grave Sites

Statements of witnesses are not always positive in respect to exact locations due to emotional stress, seasonal changes in topography or landmarks that may have been destroyed, etc., but still are the most important and reliable source of information for general or specific site location of the grave. However, if possible, information should be collected from more than one witness. If the grave's specific location is not known, it may be verified by other means.

 Site Assessment

Before the excavation can take place, a preliminary visit to the suspected site is necessary to map the area to be excavated. Above all it must be insured that the area has been cleared of surface debris. Search party personnel need to be briefed on customary elements that indicate the location of a gravesite.

The most useful indicators for a fresh, or new, gravesite are: 

• Differences in type and growth of vegetation — mixed species and disturbed growth
• Visual changes in ground surface level — depression, cracks, soil compaction
• Differences in soil composition while probing and coring — less compact, disturbed or showing contact with decomposed remains (the odor produced by sniffing a tip of the probe)

If the grave is older, oftentimes there may be no visible features to indicate a disturbance in the soil. One has to keep in mind that graves can be purposely concealed. It may be necessary to use other means of detection to reveal a general area where a grave may be located.

•  Aerial or satellite photographs
• Ground penetrating radar (GPR) - may require relatively smooth surface
• Magnetometer - works over snow and water
• Metal probe - survey natural compact strata vs. disturbed soil, may bring decomposed scent on the tip of a probe
• Metal detector - helpful if metal or bullets are in and around grave
• Cadaver dogs - may be the most effective, even in very difficult conditions, such as very old and very deep graves, when remains are skeletonized or air and ground are moist

Usefulness of the first three means may be questionable. Availability of aerial photographs is very limited and the use of GPR or a magnetometer is more of theoretical than practical interest. Those high-tech, very sophisticated instruments are dependent on the specific environment in which the grave may be located, and have to be operated by trained personnel. GPR can "see" as deep as 1.5 to 2m into the soil, depending upon soil character. Sometimes it can "see" the image or structure of a body or other materials (non-soil) at a specific depth. Applicability of the magnetometer (also called a proton magnetometer) depends on soil quality. It works better in homogeneous soils. Unfortunately, both techniques rely on the finding of soil disturbance and require a large amount of expensive equipment on the site. This equipment needs to be operated by personnel skilled in interpreting the information displayed on the computer screen in order to "translate" the patterns of soil. Additionally, covering the searched area takes a lot of time and even under the best of conditions, it may be difficult to interpret what is depicted on the computer screens.

 READ THE FULL ARTICLE HERE  

 

 

 

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